8,041 research outputs found
Eta photoproduction on the proton
Eta photoproduction experiments have proven a useful tool in the search for narrow nucleon resonances. In recent years, there has been much interest in the possible existence of the N*(1685) narrow nucleon resonance. Several experiments have been performed that rely on extracting neutron observables from deuteron target data. These have shown some evidence of narrow structure, however, no structure was observed on the proton channel. Within the A2
collaboration at Mainz, a more detailed study has been undertaken using eta photoproduction on an LH2 target (gamma p -> eta p); it has high resolution and high precision, in an attempt to overcome the predicted low photocoupling between the N*(1685) and the proton. This paper provides an overview of the experiment and detector systems, and shows the current state of the data analysis. The gamma p -> eta p total cross section is presented for the 2 gamma-decay channel. This shows no evidence of the N*(1685) in ´ photoproduction on the proton
How do patients with end-stage ankle arthritis decide between two surgical treatments?:A qualitative study
To examine how patients decide between ankle fusion and ankle replacement in end-stage ankle arthritis
Evidence on Rationality in Commercial Property Markets: An Interpretation and Critique
Periodic sharp sustained increases and then reversals in asset prices lead many to posit irrational price bubbles. The general case for irrationality is that real asset prices simply have moved too much given the future real cash flows the assets are reasonably likely to produce. A corollary for property is that observed mean reversion in real cash flows is not reflected in investor valuations, resulting in asset values being too high when real cash flows are high and vice versa. In this paper we interpret, critique and extend existing analyses of movements in real commercial property prices during the late 1980s and early 1990s.
Results Matter: Three Case Studies Comparing and Contrasting PFFM and HazOp PHA Reviews
PresentationComplete, thorough, and correct process safety management depends to a large extent on complete, thorough, and correct process hazard identification, both before and during the process hazards analysis (PHA) review. Findings from the examination of incidents and disasters in industry indicate that PHA reviews fail to identify a significant number of process hazards. This is unacceptable: we cannot manage a hazard if we don’t know that it exists, and incidents will continue to occur if PHA reviews continue to overlook process hazards. HAZOP is widely recognized as the standard for conducting thorough PHA reviews, but it is not the only technique available. In this paper, outcomes of three actual HAZOP reviews in the oil & gas industry are compared and contrasted with the results for the same facilities using Process Flow Failure Modes (PFFM). PFFM is a unique method, best described as a highly efficient, highly effective cross between FMEA and HAZOP, enhanced by a customized visual tool. Differences in the success rate of the two methodologies to identify process hazards are quantified and discussed with the aim of improving the industry success rate in identifying process hazards during PHA reviews in a cost-effective, straightforward manner
Fire and light in the western triduum: their use at tenebrae and at the paschal vigil
The stage-by-stage development of Tenebrae is described showing the extension of light-loss at Lauds on Good Friday to the three night offices of the Western Triduum. The emergence, development, and use of the hearse at Tenebrae from the eleventh century onwards is explored, together with the integration of that device into the liturgical drama that the service of Tenebrae represented. The varying number of lights used and the extinction-points are shown to be derived from differing liturgical traditions. The presence of other lights at the service is discussed; and the extinguishing of lights is shown to have a rememorative, not a utilitarian origin. The new fire ceremonies of all the Western rites, which were of Galilean origin, were deliberately adopted by the Church as part of her missionary work. An in-depth survey of the ritual surrounding the kindling of the fire and the subsequent procession with the fire into church reveals a heritage of different cultural and liturgical traditions. Not only was the threefold production of fire linked to the triple performance of Tenebrae;the new fire ceremony was integrated into the Paschal vigil liturgy because of the common theme of light; and to the former was extended the Passover motif. Not only are the geographical and liturgical origins of the Easter candle considered; an historical analysis is presented of both the Candle itself and of the ceremonial surrounding the blessing of the Candle. This ceremonial, being largely of Galilean provenance, is ex-aunined in relation to the corresponding Milanese, Mozarabic, and Roman Vigil liturgies, all of which are related to the Lucernariua of Jerusalem. The study shows that the late medieval Paschal ceremony of light was a synthesis of Roman and Galilean elements; and that a two fold tradition existed relating to the provision of light at the Vigil
An investigation of the diffuse radio emission in the galaxy cluster Abell S1136
In this thesis, I have presented my observations of the diffuse radio emission from the galaxy cluster Abell S1136, first observed by Olowin (1988 ) in the Southern Extension to the Abell et al. (1989 ) All-Sky Catalog. These observations were made with the Australian Square Kilometre Array Pathfinder (ASKAP ) telescope, as part of the Early Science program of the Evolutionary Map of the Universe (EMU ) (Norris et al. , 2011 ); a wide-field, radio continuum survey, planned for the Australian Square Kilometre Array Pathfinder (ASKAP ) (Norris et al. , 2011 ). The diffuse emission in the Abell S1136 galaxy cluster, previously identified as a radio halo in surveys with Murchison Wide Field Array (MWA ), appears to extend in a reverse S shape from the Active Galactic Nucleis (AGN s) in the core of the cluster, shown in Figure 4.1 . This emission appears consistent with a Fanaroff-Riley Type I (FRI ) type radio galaxy with a Wide Angle Tail (WAT ). The diffuse emission breaks up into several filamentary structures, which is interpreted as synchrotron emission from shock-excited electrons. I found there is evidence of filamentary structure in three distinct areas of the cluster centre, which I have labelled as: 1. The Northern Filament. 2. The BCG Filament. 3. The Southern Filament. Analysis of radio and X-ray data shows Abell S1136 to be a relaxed cluster that is likely in equilibrium. The X-ray and radio emission was found to be coincident with the centre of the galaxy cluster, located on the BCG ESO 470-20 (Lauberts and Valentijn , 1989 ). The `northern filament' showed as being a possible radio channel , either punching its way through the hot gas of the Intra-Cluster Medium (ICM ) or being constrained in some way by the ICM . In the analysis presented here, Abell S1136 does not have a cool core. There is a small centroid shift, which indicates the possibility of a slightly disturbed system, and possible interaction between Abell S1136 and PKS 2333-318. The filamentary sub-structure in Abell S1136 is quite unusual, and difficult to interpret in the framework of currently proposed models
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